Godaert



Nov. 30, 1954 w. GODAERT ,69

DEVICE FOR COMPARING THE PHYSIOLOGICAL ACTIVITY OF AN ORGAN To A STANDARD Filed Dec. 18, 1951 IN V EN TOR.

WALTER GoDhERT United States Patent@ frfie resent=inventien;re1ates to a device for. comparing die-physiological aetivitysof. an .or'g'an-to .a standard," arid It niofe rparticularly td a i device for comparin "the noise} produce'df'by',tlie 'lphysiologi'cal' activitylof an organ; such as tlie lungsof'a patient to a 'st'zindar'di' The. present. 'appplic'ation is l a contiiiuatiofi fm-part {of g the co-pendingapplication Serial-Now 134,252, filed December-2l 1949, for Eljectro-Acoustical-'and Bio Chemical Method for the Measure of Nervousfilerision (Yasofionstriction); as Well as the Estimation of the Bio-Chemical" Dosingiiofi"Blood?" I U As more fullyexplairied-in my co-pendingapplication,; L this= method co nsists in observinggtheperiodical sound pr'odtieed by lthe physiological act-ivityizof an organ 'sucli as tl'ielungs, th'e so-"calle'd breathing cycle and comparing. the same for: instance, lbyl'" a graphical; recording =with'- the; SOund-pmduced'by the correspondingf organ, forin stance, the lungs e of a normal person? From the curves recorded in this way rnedical -conclusions Withrespectto the state of health of the person whose breathing-.- cycleisexaminedcan be'drawn.- g 3 It "is i an object of thepresent invention to -p rovide'- a device for-comparing the physiological activity 1 of-an Y organ,:and particularly thesound produce'd by the lung'sofi-a patient to astandard I'tis another object'of the present inventionto provide-- an -electrogacoustical'device forthe same'purposet A Itis a-further; object-of the present invention to providea devicefwhich allows -a change of the 'stand'ard within certainlimits; l t

It is a still further object of -thepresent invention to provide an elect-ro-aeoustic-al inst-rument which'-can be operatedby the average physician without-special knowl-" edge off-the electrical principle involved; h

A device according to the present invention comprises inits broadestaspeets aithyratr'on havingka control grid- 5 and anano de lmeansf connected to--the" anode of the thyratron forimparting to the; anodeoscillations having 9 a predetermined frequency depending err-the standard, means--for generatirrg loscillationsgindependency on --the-'= activity to 'be compared-means for impartingitothecore' 53 trol grid of the thyratronwpotentialcontrolled byithe generating means, and-recording means conneted to the anode of theethyratron whereby the thy ratronisi started; ina rhythm dependent on the" activity to he compared andextinguishedqin the rhythm of the-oscillations having (54) apredetermined-frequency so that the recording means" ishactuated rhythmically independency on the activity to-be compared? Preferably a micr0phoneis= actuate'dbydthe sound producedby the physiological activity :to-be-compared,- 35 and{an-electriccircuit is connected-to-thc= microphone" and generates a potential controlled-by the-microphdney= means being providedfor imparting-to thescontrolgrid of the thyratron, the potential generated in -the electric circuit.

In a preferred embodiment-of thepresent'invention -arr amplifier =is. connected toi the' microphone and a cathod'e fqllower having the input-thereof connected to the 'ar'npli*- fififi andwanwoutput being connected-to the control grid of zthe thyrat-ron 75 lireferably, the:oscillating-stage; includes oscillating; tube hayitig {a cathodeconnected-toan oscillat-ing circuit-r includingarres' rand; a capacity-connected and parallelt y I so Preferably a tuning "cir'cuit' inemdingl a lurality/"0? variablejresis'tors 'is connected *with one end thereof to 1 the oscillating circiiit the timing 'ciicuifbeing "connected to the "gridof "the. oscillating tube;

In a preferred embodiment of the "1p resent"inventidh the oscillating stage"'conip'r'issin addition. an "amplifying tube" having a control 1 grid fed with the oscillations generated by-"the oscillating tube, the amplifying tube being biased so as jtoflgenerate "substantially" square ofitput oscillations; wllieliar supplied "to thefcontrol' grid 1 of 'ajcathode follower the output of which is connected withltlie anodefof "thethyration:

Preferably a frequency meter is' provided 'for measuring the" f equency of' -the os'cillatin' v Fig. 1 is a wiring diagram of ace-"vice"accordihg-i-to the present invfutiongand FigfZ isa diagramfor explaining the operation ofthe-- device shqwn" inFig.l l.

5 ondary 22 haviriga midpoint 32 'Whicliis -corinectedto one end of-a pot'efitiometerf 'll the 'otlier"end'-'of which is connected lover-a choke 34' tothe catliode-"26Q In cdri seq'uence" thereof the potentiometer "11 isimparted." a smooth direct' current setting fupin th'fsaine "a substantiallyf constant aired; voltage of 'which a fparf is' taken oflj by tlie 'tap'36 andj'fedto tlie'catliode 3S of'athyratrori- 40 having a control grid "42; and -an anode 44 {which are' co' fine'ct'ed,"respectively, .to thepar'ts' more described in detail hereinafter? 1 I I A n licrophone' 1s? icenfiectedftd the primary 52 "of transformer 54 the "sec6nda'ryf56 'of which is connected betwe'e'rfthjcathode '58 and -the control grid' -of a vacuum tube 62 forming-the firststage of 'a three-stagev amplifier 65 comprising-inaddition two more -stages-- consisting' iof the vacuum tubes6 4 and 66. The' vacuum tubes 62, 64 and'gateresistancecapacitance coupled with one another. The vacuum tube 66 is coupled to a vacuum tube" '68 'des'ig'ried 'as' a cathode follower (terrn edhereinafter-"the" second cathode follower) -CqI1I'leCtedtQ thefcoritrol f-grfid 42- of -thethyratrorr'40: It should be uiidefs'toodthat' the-control grid-42 is negatively biased with. respect to the cathode- 38 of the -thyratron 40' and 1 clian t's" potential undr'jthe influerice ofl the' 'sound way alien up;by'tlie 'microphone 50 hieh produceselec tric'al voltag es amplified by-the amplifier? and trans mitted tii loll lgh ih fii cathode follower 58 to the control grid 42 of the 'tliyra't'rdn 40 so th'at the latter is-fired,"- The eonnec tiofi between the microphone SOfand the control grid 420i thefltliyratron '40 is refeired to hereinafter as the "electric"' 'r'ciiitL g The oscillatiii'gj i stage, comprises" a vacuum tube '10 acting as "an foscillatin'g Jtubefand haying a cathode 72, 2. contiol'jgrid 74 and;ari anode 76'. The cathode" 72 is connected to an'oscillating "circuit consisting ,of a resistor 78 and-cgnden'serisofipparallel; v The" cone- 51 grid 7 4 of the oscillating tube 71] 'iscor'inctfe'cl to on "d 'off'the 'res is'torg' 78"by"'mearis"of fa tuning 'circiiitin ud ei 'erssza8 :15?? ense y yeletor ea" ated by the oscillating tube 70 can be changed within certain limits by an adjustment of the variable resistors 82, 84, 86.

The vacuum tube 96 following the oscillating tube 70 is connected as a cathode follower the. cathode 98 of which is connected to the control grid 100 of a vacuum tube 102 being an amplifying tube which is so biased that the tube 102 produces substantially square waves.

'The square waves poduced by the amplifier 102are fed to the control grid 104 of a vacuum tube 106 designed as a cathode follower (termed hereinafter the first cathode follower) the cathode 108 of which is connected to the anode 44 of thethyratron through a recording device 110.

The heating currents of the tubes 62,64, 66, 70 and 102 are supplied by the secondary 14, the heating currents of the tubes 68, 96, 106 are supplied by the secondary 16 and the heating current of the cathode 38 of the thyratron 40 is supplied by the secondary 18, the letters a, b, c, d, e, 3, being added to the terminals of the secondaries 14, 1 6 and 18 and the heating windings of the tubes 62, 64, 66, 68, 70, 96,102, 106 and 40, respectively.

A frequency meter 112 is connected so as to allow to measure the predetermined frequency of the oscillations generated by the oscillating tube 70 and fed to the anode '44 of the thyratron 40.

The operation of this device is as follows:

The oscillator connected to the anode 44 of the thyratron is tuned to a predetermined frequency depending on the standard such as the respiration cycle of a normal person. The normal period of inhalation of a normal man has been determined to' be three seconds. It has also been determined by way of experiment, that inorder to most readily understand the measure of the difference between the period of inhalation of'a subject as compared'to a normal man a period of time suchas one. twelfth of a second'is most suitable, and is known as biocycle. The oscillator is designed to oscillate at twenty-four cycles per second, twice the biocycle.

The microphone 50 is appliedto the organ the physiological activity, for instance the sound, of which is to be compared to the standard. As a rule this sound will be produced by the lungs of a patient so that the control grid 42 of the thyratron 40 is biased positively in the rhythm of the sound to be compared. The thyratron 40 prevents the registration or the measuring 'of the square waves produced by the amplifier 102 during the period of silence. soon as the respiratory noises begin and can be heard. In the absence of respiratory noises the'square waves are prevented from being recorded by the negative ditference of potential between the grid and the cathode of the thyratron sufiicient to cut off electron emission in the thyratron. The amplified respiratorynoises picked up by the microphone of the thyratron, result in an output which is recorded by the recording device connected in the thyratron circuit each time the poetntial of the control electrode is driven in positive direction beyond the cut off potential. The thyratron permits the registration or measuring of the square waves at one half the oscillatory frequency, namely. twelve cycles per second (the thyratron acting as a rectifier). The number of registered or measured square waves permits the determination of the extent of inhalation or expiration stated in biocycles. It is apparent that such a determination can be made since, as has been stated, the normal extent of inhalation of a normal man is determined to be three seconds. Inasmuch as the biocycle is one twelfth of a second it is apparent that it is possible to obtain a maximum of thirty-six square wave pulses for each inhalation or exhalation cycle. By counting the number of the square wave pulses and comparing them to the number obtained when examining a normal man the condition of the examined subject may be readily determined. Figure 2 of the accompanying drawings is a diagram of the intensity of sounds plotted against time as taken by the recording device 110 and it will be clear from Fig. 2 that'the thyratron 40 isfired during the time interval t1 or t2 according as the cathode voltage of the thyratron is adjusted by the adjustment of the tap 36 of the potentiometer 11. Thus it will be clear that the number .of standard cycles during which the thyratron 40 is fired can be easily ascertained with the apparatus, this number depending on the sound received by. the microphone .50." I The curves taken by the recording device 110' allow to draw important conclusions with The square waves are recorded or measured as 50 which are fed to the control grid respect to the condition of the patient from the number of cycles during which the thyratron is fired and from the shape of the curves as more fully explained in my co-pending application Serial No. 134,252.

It will be understood that each of the elements described above, or two or more together, may also find a useful application inother types of devices for comparing the physiological activity to a standard differing from the types described above.

While the invention has been illustrated and described as embodied in a device for comparing the noise produced by the lungs of a patient to a standard, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A device for comparing the physiological activity of an organ to a standard, comprising in combination, a thyratron having a control grid and an anode; means connected to said anode of said thyratron for imparting to said anode oscillations having a predetermined frequency; means for generating oscillations in electrical potentials in dependency on the activity to be compared;

means for imparting to said control grid of said thyratron a potential controlled by said generating means; and' recording means connected to said anode of said thyratron.

2. A device for comparing the physiological activity of an organ to a standard, comprising in combination, a

thyratron having a control grid and an anode; means 'connected to said anode of said thyratron forimparting to said anode oscillations having a predetermined frequency; means for generating oscillations in electrical potentials in dependency on the activity to be compared, said means including a cathode follower; means for imparting to said control grid of said thyratron -a potential controlled by said cathode follower; and recording means connected to said anode of said'thyratron. I Y

3. A device for comparing the soundproduced by the physiological activity of an organ tov a standard, comprising in combination, a thyratron having a control grid and an anode; means connected to said anode produced by the activity to be compared; means for imparting to said control grid of said thyratron a potential-- controlled by sa1d generating means; and recording means connected to said anode of said thyratron.

4. A device for comparing the sound produced prising in combination, a thyratron having a control grid and an anode; meansconnected to said anode ing a predetermined frequency; oscillations in electrical potentials sound produced by the activity to be compared, --said means for generating means including a cathode follower;"means for'impart-' prising in combination, a thyratron having a control grid and an anode; means connected to said anode the sound produced by the physiological activity to be compared; an electric circuit connected to said microphone, said-electric circuit generating apotentialcon trolled by saidmicrophone; means for imparting 'to said control grid of said thyratron the potential generated: in said electric circuit; and recording means connected to said anode of said thyratron.

of said thyratron, for imparting to said anode oscillations having a predetermined frequency; means for generating oscillations in electrical'potentials in dependency on-the sound by the physiological activityof an organ to a standard, com--;

of said thyratron for imparting to said anode oscillations havin dependency on the by the. physiologlcal activity of an organ to a standard, com

of said, thyratron for imparting tosaid anode oscillationsh-aving a. predetermined frequency; a microphone actuated by" 6: A devic'e for comparinga the soundi prodiieed' iby the-physiological activity -'of= 'an'=organ tdwastahdzirdy comprising in :co'mbina-tio'n;- c. thyratron having a 'control' gridandan anode; means connected "to said anode*ofsaidthyratron for Y imparting to saidanode oscillations having a predetermined frequency; a microphone actuatedbyqthe sound produced by the physiological activity to' be 'compared;anelectric' circuit connected to said microphone andlinclu'ding acathode follower, said 'electric circuit generating -'a potential 'controlled' 'by said micro-"- phone; a connection between said "cathode fo'llower and said control grid f sa-idthyratron 'so 'as to 'impartto the 1 same a the potential generated in said electrio"circuit; and recording means connected rto "said anode of said thyratron.

7 A device "for xcomparing the} sound produced by the physiological l activityu of* an i organ to a standard, comprising :in combination, a :ithfyratron having a control grid'and' an='anode; means connected to 'sai'd anode of" said thyratron. for imparting to said "anode oscillatio'ns havinga predetermined frequency; a'microphone-actuated by the sound produced by the physiological activity to. be "compared? an amplifier connected to said micro-'- phone;- a cathode-follower havingtheinput thereof 'conlower being connected to-the-control gridof said thyratron'so as toiimpart to the same potentials dependent onthe sound prodnced by the physiologicaltaetivity to be compared; and recording means connected to said anode of said 'thyratron, 3

8. A device for comparing the physiological activity of- "an organ 'to" a standard," comprising in combination, a 'thyratron having l a control' grid and an anode}: means 1 including a *cathbde follower" "connected to said anode ofi said thyratron' for-'impa'rting 'to-*said anode oscillations having a=predetermined frequency;- means' for gen erating oscillatio'ns in -'ele'ctrical' potentials-"in depende'ncy on the activity'to' be compared; means for imparting to said control 'grid of said 'thyratron a -potentialwcontrolled by said generating means; and recording means con-'- necte'd 'to said anode of said thyratron:

9:- A device-fore comparing the-physiological "activity. of-an organ to a standard,comprising in combination; a'thyratron shaving a control grid and 'an anode; an os-' ,cillating stage connectedto said anode-of-saitl thyratron, said oscillating stage including an oscillating tube" generating oscillations having a predetermined frequency; means for generating;oscillations in electricalf -potentialsin dependency on the activity to be comparedjm'eans forirnpartingto said control gridof saidthyratron 'a po-' 5 te'ntial controlled by Saidgenerating means? and record ing-meansconnected to saidanQde of said ethyratron.

l0."A device ro'r comparing the physiological activity of -an organ toastandard, comprising in combination,"

a thyratron having a control 'grid and an anode an oscillating stageconnected'to said anode of said thyratr'on," said oscillating stage including an oscillating tube hav-" ing' a cathode; an oscillating circuitincltiding'aresistor and "a 'capacity' connectedin parallel-with :each*other;

said oscillatingcircuit being connected "to said ca't-hode of said-oscillating tube, "said oscillating stage, generatingoscillations hElVlI'lgt a predetermined frequency; means fo'rgenerating oscillations iii-electrical potentials inL'de'?" pendency on the activity to :be .comparedf'meansfora N imparting 'to" said 'control' grid 10f"'said"thyratron a p05 tential controlled by'said generating means; and record" ing. means connected'to said anode of said thyratron.-'

11; A device for 'comparingsthe physiological activity,

of anorgan'to'ia standard; comprising 'incombi'nation', a F

thyratron rhaving'a control grid andxan anode; an os.'-'-' cillating stage connected "to said anode of said: thyratron said oscillatingi stage including an oscillating tube zhav-" in'gacath'ode, a gridand anianode;ancScillatingycir cuit including a constant' resistor and a capacitycons nected in parallel" .Witheaclr other; said oscillatingficir cuit being connected :to :said "cathode :of said oscillating tube; atunin'g 'circuitincludin'g a plnralitypfuvariable resistors connected with one end 'thereofto saidoscilla't ing circuit, said tuning circuitbeing,connected to said grid of said oscillating tube, said oscillating stage generating oscillations having a predetermined frequency; means for generating oscillations in electrical potentials in dependency on the activity to be compared; means for imparting to said control grid of said thyratron a potential controlled by said generating means; and reingecircuit including a pluralityiof variable resistorsf'co nectedwith one-endthereof-"toisaid 'cseill'ating circuity anemone 12. A devicezfor comparingthe: physiological-activity v ofan organ'to a standard; comprising in combination, thyratron shaving =a "control grid i and r ani'ano'deg an- 'osc latin'gstage connected toasaid wanode of said i 'rthyrat'ton, a saidoscillating -stage including "an oscillating' tu'be lgen crating oscillationsi'having 1 a lpredet-ermined cfrquencyy" an amplifying tu'betforming' partt"of said oscillating stage andhaving a control grid fed with the-oscillations hav ing a predetermined frequency andfi generated by Sald oscillating tube, said amplifying tube-beingfbiased to generate substantially square output-Iosc'i l'lati'on substantially 11 square output oscillations of:: said amp fying tube being supplied ito said anodeiof said th-yra tron; means for generating osci llat ions" in :electrical: ipo tentials in dependency" on the: aetivityr' to beiconrparemzz means forimparting to said control grid of saidtthyrat ro'n a ipotential' controlled -by I said genet-atingw meanxi and I recording r means connected to' said 'anode of" said thyra-i 'cillating stage connected tosaid anode t ofvsaid thyratromii said "oscillating stage includiiig ,;an"oscillating: tube f'gencrating oscillations having. a predeterminedi frequency an amplifying-tube formingpart 'of said-oscillating stag andhaving'a control grid fedwiththe oscillatibnsfihaV ing a predetermined frequencyi and generated by said oscillating 3 tube, said amplifyingitube P being biased so as-to generate substantially square outp'ut osc'illation 1 a cathode 'follower having 'acontrols gr'i onne'cted the *outpu't of' 'said amplifying'jttlbe; the 'ontput'iofttsai cathode z'follo'wer being 'connected'pwith saidianodei of said thyratron so asto irnpart to th'e same potentials cor responding to said substantially square output oscillations of said 'amplifier; means 'for generating :oscillations n? electrical potentials in dependency on th'e activit' to be compared? means for imparting to said control: ridof said thyr-atrona potential controlled by isa id generatlb ing means; and recording means: connected to said ano'de of said thyratron;

14."- A device for comparing the physiological' activity; of an organ to a sta'ndard, comprising :in cornbinatio i a thyratron having a control grid and an anodeg'r an Iosr-r cillating stage connected to' said'anode of said Tthyratrong said oscillating stage including an Ilo scil l-a-ting tub'e"':hav-" ing a cathode," a *grid I and an anodes an oscillating-mintcuit including a constant resistor -and-a capacito'r cons nected inparallel Witheach-Qthr said oscillating-circuit being connected to said A cathode of sa-i'd oscillating tube:- a toning circuit including a plurality ofiivariablei'lr sistors connected with one "end thereof to said oscillating: circuit, saidtun'ing circuit being connected to 'saidfgridiofsaid-oscillating tube; said oscillating- 'tube generating -oscillat-ions having a predetermined frequency; anriamplia fying tube" forming part'of' said oscillating stage-"and have ing a control grid fed-with the oscillations'xhaving 'a ipre' determined fr'equency' andr-igenerat'ed by 'sa'idi ios'tii'llatih gi tribe;- said amplifying. tubelbeing -lbiase'd so as to lgens'. eratev substantially 'square ontpnt 'os'eillationsg saidfisub' stant-ially square-output oscillations: 'of said ampli-fyin tube -being- 'supplied 'to I said anode=::of isaid ithyratron;c. means for generating oscillations in "electrical potentials. in dependency on the activity to be comparecly meansifdr. imparting to said control grid of said thyratron a potentialt controlled by said generatin'g means; andtre'cordingd means connected tosaid anode ofsaid' thyratronvl5.' AJdevice for comparing the physiological?activity of an organnto a standard,"compris'ingzin combination; P thyratronxhaving'a controtgrid and anjanodeg an osc lating stage connected to sa'idanode of said =tl'iyratron;i

F E said -"osci1latin'g stage including an oscillating cube haw t a t in'g 'a cathodegla grid and-"an anode?*an'oscillating'circuit including a constant resistor and a capacity connected in parallel with each' other, Said'QScillat-ing "circuit being connectedto said cathode of'said'oscillating-tube: a tlln' saidtriningcir'cuit bingwonnected to said grid"*bf-said' oscillating tube, said oscillating tube generating oscillations having a predetermined frequency; an amplifying tube forming part of said oscillating stage and having a control grid fed with the oscillations having a predetermined frequency and generated by said oscillating tube, said amplifying tube being biased so as to generate substantially square output oscillations; means for generating oscillations in electrical potentials in dependency on the activity to be compared; means for imparting to said control grid of said thyratron a potential controlled by said generating means; and recording means connected to said anode of said thyratron.

16. A device for comparing the physiological activity of an organ to a standard, comprising in combination, a thyratron having a control grid and an anode; an oscillating stage connected to said anode of said thyratron, said oscillating stage including an oscillating tube having a cathode, a grid and an anode; an oscillating circuit including a constant resistor and a capacity connected in parallel with each other, said oscillating circuit being connected to said cathode of said oscillating tube; a tuning circuit including a plurality of variable resistors connected with one end thereof to said oscillating circuit, said tuning circuit being connected to said grid of said oscillating tube, said oscillating tube generating oscillations having a predetermined frequency; an amplifying tube forming part of said oscillating stage and having a control grid fed With the oscillations having a predetermined frequency and generated by said oscillating tube, said amplifying tube being biased so as to generate substantially square output oscillations said substantially square output oscillations of said amplifying tube being supplied to said anode of said thyratron; a microphone actuated by the sound produced by the physiological activity to be compared; an electric circuit connected to said microphone, said electric circuit generating a potential controlled by said microphone; means for imparting to said control grid of said thyratron the potential generated in said electric circuit; and recording means connected to said anode of said thyratron.

17. A device for comparing the physiological activity of an organ to a standard, comprising in combination, a thyratron having a control grid and an anode; an oscillating stage connected to said anode of said thyratron, said oscillating stage including an oscillating tube having a cathode, a grid and an anode; an oscillating circuit including a constant resistor and a capacity connected in parallel with each other, said oscillating circuit being connected to said cathode of said oscillating tube; a tuning circuit including a plurality of variable resistors connected with one end thereof to said oscillating circuit, said tuning circuit being connected to said grid of said oscillating tube, said oscillating tube generating oscillations having a predetermined frequency; an amplifying 1 tube forming part of said oscillating stage and having a control grid fed With the oscillations having a predetermined frequency and generated by said oscillating tube, said amplifying tube being biased so as to generate substantially square output oscillations said subtsantially square output oscillations of said amplifying tube being supplied to said anode of said thyratron; a microphone actuated by the sound produced by the physiological activity to be compared; an electric circuit connected to said microphone and including a first cathode follower, said electric circuit generating a potential controlled by said microphone; a connection between said second cathode follower and said control grid of said thyratron so as to impart to the same the potential generated in said electric circuit; and recording means connected to said anode of said thyratron.

18. A device for comparing the physiological activity of an organ to a standard, comprising in combination, a thyratron having a control grid and an anode; an oscillating stage connected to said anode of said thyratron, said oscillating stage including an oscillating tube having a cathode, a grid and an anode; an oscillating circuit including a constant resistor and a capacity connected in parallel with each other, said oscillating circuit being connected to said cathode of said oscillating tube; a tuning circuit including a pluralityof variable resistors connected with one end thereof to said oscillating circuit, said tuning circuit being connected to said grid of said oscillating tube, said oscillating tube generating oscillations having a predetermined frequency; an amplifying tube forming part of said oscillating stage and having a control grid fed with the oscillations having a predetermined frequency and generated by said oscillating tube, said amplifying tube being biased so as to generate substantially square output oscillations, said substantially square output oscillations of said amplifying tube being supplied to said anode of said thyratron; a mircophone actuated by the sound produced by the physiological activity to be compared; an amplifier connected to said microphone; a second cathode follower having the input thereof connected to said amplifier, the output of said second cathode follower being connected to the control grid of said thyratron so as to impart to the same potentials dependent on the sound produced by the physiological activity to be compared; and recording means connected to said anode of said thyratron.

19. A device for comparing the physiological activity of an organ to a standard, comprising in combination a thyratron having a control grid and an anode; an oscillating stage connected to said anode of said thyratron, said oscillating stage including an oscillating tube having a cathode, a grid and an anode; an oscillating circuit including a constant resistor and a capacity connected in parallel with each other, said oscillating circuit being connected to said cathode of said oscillating tube; a tuning circuit including a plurality of variable resistors connected with one end thereof to said oscillating circuit, said tuning circuit being connected to said grid of said oscillating tube, said oscillating tube generating oscillations having a predetermined frequency; an amplifying tube forming part of said oscillating stage and having a control grid fed with the oscillations having a predetermined frequency and generated by said oscillating tube, said amplifying tube being biased so as to generate substantially square output oscillations, said substantially square output oscillations of said amplifying tube being supplied to said anode of said thyratron; a microphone actuated by the sound produced by the physiological activity to be compared; an amplifier connected to said microphone; a second cathode follower having the input thereof connected to said amplifier, the output of said second cathode follower being connected to the control grid of said thyratron so as to impart to the same potentials dependent on the sound produced by the physiological activity to be compared; and recording means inserted between the cathode of said cathode follower and said anode of said thyratron.

20. A device for comparing the physiological activity of an organ to a standard, comprising in combination a thyratron having a control grid and an anode; an oscillating stage connected to said anode of said thyratron, said oscillating stage including an oscillating tube having a cathode, a grid and an anode; an oscillating circuit including a constant resistor and a capacity connected in parallel with each other, said oscillating circuit being connected to said cathode of said oscillating tube; a tuning circuit including a plurality of variable resistors connected with one end thereof to said oscillating circuit, said tuning circuit being connected to said grid of said oscillating tube, said oscillating tube generating oscillations having a predetermined frequency; an amplifying tube forming part of said oscillating stage and having a control grid fed with the oscillations having a predetermined frequency and generated by said oscillating tube, said amplifying tube being biased so as to generate substantially square output oscillations, said substantially square output oscillations of said amplifying tube being supplied to said anode of said thyratron; a microphone actuated by the sound produced by the physiological activity to be compared; an amplifier connected to said microphone; a second cathode follower having the input thereof connected to said amplifier, the output of said second cathode follower being connected to the control grid of said thyratron so as to impart to the same potentials dependent on the sound produced by the physiological activity to be compared; a frequency meter connected to said first cathode follower; and recording means inserted between the cathode of said cathode follower and said anode of said thyratron.

No references cited. 

